The condition may be diagnosed by a neurologist or geneticist. An infant may be diagnosed through standard newborn screening tests.The process to diagnose carnitine deficiency starts with a health history and a physical exam. Your healthcare provider will ask about your symptoms and past health conditions. He or she may also ask about your family’s health history. The physical exam may include a neurological exam. Tests may also be done. These include: Blood tests. These are done to check the levels of carnitine in the blood. They also check for creatine kinase. This shows muscle damage. And they check for enzymes in the blood that can show liver disease. Urine test. This test looks for a protein called ketones. Exercise tests. These help identify the type of metabolic problem. Genetic test. This kind of test can confirm primary carnitine deficiency. Heart tests. Tests such as echocardiography can show if the heart is affected.